The present invention relates to a manufacturing method of a semiconductor device, and in particular, to a technique effective when applied to a manufacturing method of a semiconductor device using liquid immersion exposure.
The liquid immersion exposure is an exposure system in which in a minute gap between a lens and a semiconductor wafer, a water film (meniscus) is formed with the use of the surface tension of water, whereby the minute gap between the lens and a surface to be irradiated (semiconductor wafer) is caused to have a high refractive index, which makes it possible to increase the effective numerical aperture (NA) of the lens to a higher level than normal dry exposure. Because a finer pattern can be resolved by increasing the NA of a lens, the liquid immersion exposure is being put to industrially practical use.
Japanese Unexamined Patent Application Publication No. 2006-108564 (Patent Document 1) describes a technique in which, in order to make the surface layer of a resist film hydrophilic, an oxide layer is formed over the surface layer of the resist film by irradiating the resist film with vacuum ultraviolet light while a silicon substrate is being exposed to an active oxygen atmosphere.
Japanese Unexamined Patent Application Publication No. 2008-235542 (Patent Document 2) describes a technique in which, in liquid immersion lithography, exposure processing can be performed while a liquid is being prevented from flowing outside a wafer even when an area near to the outer periphery of the wafer is exposed. Specifically, a liquid repellent agent layer is provided over the outer peripheral end surface of the wafer and the peripheral portion of the end surface.
Japanese Unexamined Patent Application Publication No. 2009-117873 (Patent Document 3) describes a technique in which a substrate is wetted in advance by supplying a pre-wetting liquid before liquid immersion exposure, so that an immersion liquid is supplied between the wetted substrate and a projection system.
Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2006-528835 (Patent Document 4) describes a technique with respect to an immersion scanner provided with a means for preventing a gas bubble from appearing in an immersion liquid and for removing a gas bubble.
Japanese Unexamined Patent Application Publication No. 2009-88552 (Patent Document 5) describes a technique with respect to a lithography apparatus in which an influence of a bubble in an immersion liquid, which may affect the imaging quality of immersion lithography, is reduced.